change to:
30 13 * * 1-5 $HOME/my_script.sh > $HOME/my_script.log 2>&2
to get stdout and stderr output.
I have seen this before - where the environment is NOT set up correctly when running from crontab
You may need to set up expected environmental variables manually.

you need to take the logs for the cron job . Most likely its a env variable issue as cron does not set your env variables by default. You need to check the cronrun log file to find the details . Defile the exact path instead of defining a variable.($HOME/my_script.sh )

change to:
30 13 * * 1-5 $HOME/my_script.sh > $HOME/my_script.log 2>&2
to get stdout and stderr output.
I have seen this before - where the environment is NOT set up correctly when running from crontab
You may need to set up expected environmental variables manually.

Yeah, like you said, I defined some variables in that particular script. Probably these variables are not recognised by the Unix environment? So what should I do in such cases?

Dear Friends,
I have Red Hat Linux Enterprise version 6.3. running SAP and oracle.
I have created one crontab for user orasid to execute one job periodically.
But it is not executing. I have checked crontab service is running.
Please help in the matter.
Regards,
Bhagawati Pandey... Red Hat

I have a script which name is sicaklik.sh
It is in the root directory.
I can run manually but I want to run automatically every 3 minutes but it is not working. WHY?
#whoami
root
#crontab -l
#ident "@(#)root 1.21 04/03/23 SMI"
3 * * * * sh ./sicaklik.sh
#ls -l sicaklik*...... Solaris